Characterizations of the polynomial numerical hull of degree k
โ Scribed by James V. Burke; Anne Greenbaum
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 158 KB
- Volume
- 419
- Category
- Article
- ISSN
- 0024-3795
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โฆ Synopsis
Six characterizations of the polynomial numerical hull of degree k are established for bounded linear operators on a Hilbert space. It is shown how these characterizations provide a natural distinction between interior and boundary points. One of the characterizations is used to prove that the polynomial numerical hull of any fixed degree k for a Toeplitz matrix whose symbol is piecewise continuous approaches all or most of that of the infinite-dimensional Toeplitz operator, as the matrix size goes to infinity.
๐ SIMILAR VOLUMES
The polynomial numerical hull of degree k for a square matrix A is a set designed to give useful information about the norms of polynomial functions of the matrix; it is defined as |p(z)| for all p of degree k or less}. While these sets have been computed numerically for a number of matrices, the
We show that the simple matroid PG n -1 q \PG k -1 q , for n โฅ 4 and 1 โค k โค n -2, is characterized by a variety of numerical and polynomial invariants. In particular, any matroid that has the same Tutte polynomial as PG n -